Rotor balancing for distribution valve

Abstract

A rotor balancing arrangement is provided for use in a distribution valve to ensure hydrostatic balancing of a rotor located in the distribution valve. Some balancing arrangements provide areas equally spaced around the peripheral surface, each being exposed to the same pressure, however, they are limited to valves which rotate only through a limited arc of rotation. Other valves which rotate provide balancing grooves around portions of the peripheral surface but do not provide any control for the pressure that migrates axially in both directions along the peripheral surface of the rotor. In the subject arrangement, pressure fields of a predetermined size are located on a peripheral surface of a rotor circumscribing first and second outlet ports which open to opposite sides of the rotor. The size of the pressure fields is determined by the relationship of the diametrical clearance between the rotor and a bore with respect to the operating pressure of the system. This arrangement ensures that the differential forces acting on opposite sides of the rotor are minimized thus eliminating rotor sticking.

We claim: 
     
       1. In a distribution valve having a housing defining a bore and a plurality of distributor passages in communication with the bore, a rotor located in the bore and adapted to rotate, said rotor having a peripheral surface, an axial passage located therein in selective communication with a source of pressurized fluid, and a pair of outlet ports in continuous communication with the axial passage and opening to the peripheral surface on opposite sides of the rotor and in selective communication with the distributor passages of the valve housing, the improvement comprising: means for establishing pressure fields of a predetermined size relative to the diametrical clearance between the rotor and bore and the normal operating pressure so that a differential force acting to cause eccentricity of the rotor in the bore is minimized thus eliminating rotor sticking, said pressure fields being disposed on opposite sides of the rotor and each circumscribing the respective one of the pair of outlet ports.   
     
     
       2. The distributor valve as set forth in claim 1, wherein the establishing means includes first and second grooves formed on the periphery of the rotor respectively circumscribing each of the outlet ports and communicating with a low pressure zone. 
     
     
       3. The distributor valve, as set forth in claim 2, wherein the normal operating pressure is above 55,000 kPa. 
     
     
       4. The distributor valve, as set forth in claim 2, wherein said diametrical clearance between the rotor and the bore is selected from the range of 0.0025 to 0.005 millimeters. 
     
     
       5. The distributor valve, as set forth in claim 4, wherein said plurality of distributor passages in the housing intersect the bore in two different axially spaced planes, and each of said outlet ports exit on the peripheral surface of the rotor in axially offset relation to the other and respectively aligned with the two different planes of distributor passages. 
     
     
       6. The distributor valve, as set forth in claim 5, wherein the housing includes a delivery passage connected to said source of pressurized fluid and intersecting said bore axially spaced from the distributor passages, and the rotor includes a plurality of evenly spaced inlet ports opening around the peripheral surface and in communication with the axial passage for selective communication with said delivery passage. 
     
     
       7. The distributor valve, as set forth in claim 6, wherein a plurality of evenly spaced axial slots are respectively located on the peripheral surface of the rotor between the inlet ports, said slots being in communication with said low pressure zone. 
     
     
       8. In a rotor adapted for use in a fuel injection distributor valve, said rotor having a peripheral surface the improvement comprising: a plurality of inlet ports spaced angularly around the peripheral surface of the rotor;   a plurality of axial slots respectively located around the peripheral surface of the rotor between the inlet ports;   an axial passage defined in the rotor and connected at one end to the plurality of inlet ports;   first and second outlet ports connected to the axial passage and respectively exiting on the peripheral surface of the rotor on opposite sides thereof and axially spaced from the inlet ports; and   first and second grooves formed on the peripheral surface of the rotor respectively circumscribing the outlet ports and connected to the axial slots, said first and second grooves being adapted to establish a pressure field of a predetermined size on the peripheral surface to hydrostatically balance the rotor.   
     
     
       9. The rotor, as set forth in claim 8, wherein said outlet ports exit on the peripheral surface of the rotor axially offset from each other. 
     
     
       10. The rotor, as set forth in claim 9, wherein said pressure fields are substantially square in shape, and extension grooves connect the perimeter of one of the pressure fields with the axial slots. 
     
     
       11. The rotor, as set forth in claim 10, wherein said pressure fields each have two sets of parallel sides, one of the sets of parallel sides of each pressure field extend axially on the peripheral surface of the rotor, and the groove extensions of the one pressure field extend axially from the parallel sides to the axial slots. 
     
     
       12. The rotor, as set forth in claim 11, wherein one of the other two parallel sides of one of the pressure fields circumscribing one outlet is located circumferentially around the peripheral surface of the rotor diametrically opposed to the other outlet. 
     
     
       13. The rotor, as set forth in claim 12, wherein an annular groove is defined on the rotor adjacent the plurality of inlet ports and axially spaced on the opposite side of the inlet ports relative to the first and second outlet ports. 
     
     
       14. The rotor, as set forth in claim 13, wherein a second annular groove is defined on the rotor axially spaced further from the inlet ports than the first annular groove and adapted to define a land on the rotor between the first and second annular grooves.